The project involves studies of DNA tumor viruses of the papovavirus group and concerns mapping viral genes and regulatory signals for the normal viral development and oncogenic function in mammalian cells. Experiments include transformation of human cells by a human virus, BK virus and mapping of the transforming virus to determine the nature of mutation in the BK viral genome for effecting a stable association with, and a subsequent malignant change of its natural host cell. The respective functions for oncogenesis and viral DNA replication of BK virus and SV40 will be compared with regard to their sequence relatedness and complementation properties. Studies also center on mapping and sequence analysis of control signals of the viral genes in order to understand their regulatory mechanisms for gene expression. BIBLIOGRAPHIC REFERENCE: Khoury, G., Howley, P., Israel, M., Brown, D. and Lai, C.-J.: The papovaviruses: Their molecular biology and potential etiology in human disease. In Allison, F., Jr. and Rothschild, H. (Eds.): Human Diseases Caused by Cancer: Recent Developments, New Orleans, Oxford University Press, 1977, in press.